Packet data serving node initiated updates for a mobile communication system

ABSTRACT

A packet data serving node ( 106 ) initiates a packet data session update procedure with the RAN by passing a session update message containing packet data session parameters associated with at lease one packet data service) to a packet control function ( 111 ) which may be part of a radio access network ( 110 ). The session parameter may include a packet data service inactivity timer, QoS parameters, user information or any other session related parameters. Packet control function ( 111 ) examines the PSDN code and inhibits tearing down the link (A 10 /A 11 ) between PCF ( 111 ) and PDSN ( 106 ). Further, if a handoff occurs, the BS passes the packet data session parameters associated with each of the service instances to the MSC that in turn passes them on the target BS of the handoff.

BACKGROUND OF THE INVENTION

The present invention pertains to mobile communications and moreparticularly to the transfer of packet data parameters during a packetdata communication session.

A mobile station (MS) couples through a radio access network (RAN) and apacket data serving node for access to packet data applications such asemail, streaming video or web browsing packet data services. A packetdata inactivity timer is associated with the various packet dataservices, supported by the network. When the packet data inactivitytimer associated with one of the active service instances expires, theBS transitions the packet data service state from the active/connectedstate to a dormant state by releasing any traffic channels associatedwith the call.

The 3GPP2/TSG-S Standards Development Organization recently approved theuse of a realm configured packet data session dormancy timer feature(RC-PDSDT). This allows the packet data inactivity timer to beconfigured by the type of packet application in use, the Quality ofService assigned to the service, user profile information, or othersession related parameters. The inactivity timer is stored on a AAAserver (Authentication, Authorization and Accounting) in the packet datanetwork.

In order to support the AAA based inactivity timer feature, the basestation controller needs the packet data service inactivity timer oncethe service type is determined. The AAA server uses the informationreceived during the packet data call setup to obtain the associatedpacket data inactivity timer from the AAAL database.

In the current IS-2001 (IOS) specification, it is not possible for thepacket data serving node to initiate transfer of any packet dataparameters or information to the radio access network during an activeor a dormant packet data session. The IOS standard currently does notsupport any procedure that can support this feature or any other featurewhich requires a transfer of packet data session parameters to the RAN.The only current operation of the PDSN is to initiate a release of anactive or dormant packet data service. The PDSN initiates this releaseprocedure by sending an update message to the packet control function(PCF). This is the only use of the update message currently approved bythe IOS standard.

Accordingly, it would be highly advantageous for a PDSN to initiate atransfer of any packet data parameters required to support a packet datafrom call to the radio access network without completely tearing downthe connection between the packet data serving node (PDSN) and the radioaccess network under current IS2001 IOS standards.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram of a mobile communication system in accordancewith the present invention.

FIG. 2 is a message flow diagram in accordance with a preferredembodiment of the present invention.

FIG. 3 is a data layout diagram of an A11 registration update message inaccordance with a preferred embodiment of the present invention.

FIG. 4 is a message flow diagram of another embodiment of the presentinvention.

FIG. 5 is a data layout diagram of a cause value portion of an A9 updateA8 message in accordance with a preferred embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The packet data inactivity timer is a timer which is used to measure theduration of inactivity of a packet data service instance. Delaysensitive applications such as streaming video for example may require arelatively small inactivity timer value. Other less delay sensitiveapplications such as email access or web browsing may require arelatively longer packet data inactivity timer. For the case a packetdata session is supporting multiple service instances at a given time.

FIG. 1 is a block diagram depicting a mobile communication system 100 inaccordance with a preferred embodiment of the present invention.Preferably, communication system 100 is a system in accordance with thewell-known Telecommunications Industry Association/Electronic IndustriesAssociation Interim Standard 2001-A (TIA/EIA IS-2001 IOS).

System 100 comprises mobile network equipment and a mobile communicationunit. The mobile network equipment, or communication infrastructure,comprises base stations (BSs) 120 and 130, mobile switching center (MSC)115, packet control function (PCF) 111, and packet data serving node(PDSN) 106. PCF 111 and base station 130 comprise a Radio Access Network(RAN) 110.

As is well-known in the art, a base station BS comprises a base stationcontroller BSC 131 and one or more base transceiver systems (BTSs) 132,133. A mobile switching center (MSC) 115 comprises a switch 116 and acall controller/mobility manager 117. The communication infrastructureis also preferably networked to the Internet 101 via PDSN 106 oralternatively networked to some other internet or intranet (not shown).

AAAL (Authentication Authorization Accounting Local) server is coupledto PDSN 106 and provides storage for various parameters includinginactivity timers and other packet data session parameters, and userprofile information required by the system to support packet data calls.Mobile station 140 preferably comprises a CDMA-capable mobile devicethat communicates with BS 120 and 130 via the CDMA2000 (TIA/EIA/IS-2000)or HRPD wireless air interfaces (TIA/EIA/IS-856: CDMA2000 High RatePacket Data Air Interface Specification). This mobile device can be acell phone, pager and internet capable device or any combination ofthese functions. For simplicity, only two BSs and one MS are shown inFIG. 1.

The present invention is preferably implemented using softwaretechniques and technologies well-known in the art. In the preferredembodiment, the present invention is implemented in software stored onthe memory devices and executed by processors of the MSC 115, BSC 131,PDSN 106 and PCF 111. For example, the method described relative to FIG.2 is preferably implemented in PSDN, PCF, and BS software.

Typically, mobile station or device 140 couples through base station130, through PCF 111, through PDSN 106 to internet 101. In accomplishingthese links, signaling information is transmitted via the A9 and A11links between base station controller 131. Further, link A8 isestablished between base station 130 and PCF 111 for bearer traffic.Link A9 between base station 130 and PCF 111 is used for signalinginformation. Further links are established between PCF 111 and PDSN 106.Link A10 is set up between PCF 111 and PDSN 106 for bearer traffic andsimilarly, link A11 between PDSN 106 and PCF 111 is used for signalinginformation. Bearer traffic may now flow between mobile station 140 andthe internet 101.

In the present IS-2001 IOS standards, sending of the current signalingmessage from the PDSN to the PCF during an existing packet dataconnection (dormant or active) will result in the release of the A8 andA10 bearer connection. In a preferred embodiment, the PDSN 106 willobtain the inactivity timer associated with the packet data serviceinstance, and transmit it to base station 130. If more than one serviceinstance is active, the packet data session at BS 130 will transition todormant when the last inactivity timer expires. If done under thepresent IOS standards, link A10 will immediately be torn down when themessage is sent. Therefore, in a preferred embodiment, an A11registration update message will be modified to transfer sessionparameters such as the inactivity timers, quality of service parameters(QoS), or any other session related parameters requiring transfer fromthe PDSN to the PCF 111 and base station 130, and be able to indicatewhether the message is used to release or update the packet datasession.

The AAA based inactivity timer feature provides the communication systemoperator with the capability to enhance the efficiency of the RadioAccess Network (RAN) 110 radio resources by providing a mechanism tostatically configure the packet data session inactivity timer valuebased on the realm, application, or QoS parameters or associated withthe service instance. The inactivity timer associated with the packetdata connection is used by the serving BS 130 to transition thecorresponding packet data session to the dormant state after it expires.If the mobile station 140 is supporting multiple active packet dataservices, the entire packet data session transitions to the dormantstate when the last inactivity timer expires. If an inactivity timerassociated with the packet data connection is unavailable or not passedby PDSN 106, a pre-provisioned default inactivity timer at the BS shallbe used.

Referring to FIG. 2, mobile station 140 may be in a dormant or activesession 150. In a preferred embodiment of the invention, PDSN 106 willsend a message 151 (All-Registration Update) to PCF 111 to indicate thevalue of a packet data inactivity timer, QoS parameters, other sessionrelated parameters, or user profile information. Typically, transmissionof message 151 from PDSN 106 to PCF 111 results in the release of theA10 bearer connection. The PDSN 106 is modified to send aA11-registration update message 151 including session parameters such asthe inactivity timer for a the packet data service accessed by mobilestation 10. PDSN sends an inactivity timer for each packet dataconnection requested by the mobile. PDSN 106 also initiates a timerTSESUPD.

PDSN 106 will generate this message 151 and transmit it to the PCF 111.The parameters transmitted may include an inactivity timer, quality ofservice (QoS) parameters and/or other packet data session parameters.The inactivity timer and/or other parameters are transmitted in a normalvendor/organization specific extension (NVSE) element. See FIG. 3.

With reference to FIG. 3, the NVSE will have an application data field205 in which the PDSN code will be set to 20H (hexadecimal) to indicatethat the message is being sent to update a packet data connection asopposed to releasing a connection which is the present function of thismessage. The PDSN CODE value of 20H is new and indicates a packet dataconnection update. The NVSE 200 is shown. The application subtype field207 will indicate the packet data session parameter transmitted is apacket data inactivity timer. The application data field will indicatethe value of the inactivity timer 209.

Referring again to FIG. 2, PCF 111 is modified such that when itreceives the A11-Registration Update message 151 with a PDSN code of20H, it will refrain from tearing down the connection between it and thePDSN 106.

Typically, the A9-update-A8 message is transmitted from base station 130to the PCF 111. In the preferred embodiment of this invention, thismessage 152 becomes a bi-directional message and PCF 111 will transmitthis message 152 to base station 130. The A9-update-A8 message 152 isnow used to transfer or update packet session related parameters fromPCF 111 to base station 130. These parameters include the inactivitytimer and/or other packet data session parameters such as quality ofservice (QoS) parameters. A new session parameters element is added tothe A9-update-A8 message to carry the new or updated parameters. A newcause value 225 of the A9 update A8 message 152, see FIG. 5, (sessionparameters update=7B hexadecimal) indicating the purpose of the message152 is also added. The A9-update-A8 message 152 is then transmitted fromPCF 111 to base station 130. PCF 111 also initiates a timer TUPD9. An A8bearer connection between base station 130 and PCF 111 is not requiredto support the preferred embodiment.

The A9-update-A8 ACK message is typically transmitted from PCF 111 tobase station 130 and it acknowledges the A9-update-A8 message. In thepreferred embodiment of the invention, the A9-update-A8 ACK message 153is modified to be a bi-directional message. The message 153 will betransmitted from base station 130 to PCF 111 in response to theA9-update-A8 message sent in the reverse direction. The A9-update-A8 ACKmessage will be transmitted from base station 130 to PCF 111. PCF 111then stops timer TUPD9. Then, PCF 111 sends an A11 registration ACKmessage 154 to PDSN 106.

If the BS 130 responds with an indication in the A9-Update-A8 ackmessage to the PCF 111 that the new or updated session parameter was notrecognized or rejected for some reason, the PCF 111 indicates this tothe PDSN 106 in the A11-Registration ack message.

If the PCF 111 fails to respond with A11-Registration Ack message to thePDSN 106 initiated packet setup, PDSN 106 shall assume that the sessionupdate procedure failed. The PDSN 106 may attempt to resend theA11-Registration Update message to the PCF 111 a configurable number oftimes.

As can be seen in the above explanation, with minimal modifications tothe PDSN 106, PCF 111 and base station 130, a packet data inactivitytimer, or any other packet data session parameters such as quality ofservice parameters, etc. may be transferred from the packet data servingnode to the radio access network. Prior to these modifications which area preferred embodiment of the present invention, no such transmission ofsystem parameters was possible. When implemented, the AAA basedinactivity timer feature can be retrofitted to existing RANs and PDSNs.By adding new fields to existing messages and making other messagesbi-directional, a great benefit of parameter passage between packet dataserving nodes and mobile radio access networks is achieved. A furtherbenefit is that retrofit of existing packet data server serving nodesand RANs is readily accomplished by adding the PDSN code element to theA11-Registration Update message in previous versions of the standard.

If a PCF running an older version of software which does not supportPDSN initiated session updates, as described above, receives anA11-Registration Update message from the PDSN with a code valueindicating session update, the PCF shall reject the session updateattempt by ignoring the message, but shall not release the packet datasession.

Further, If a PCF or BS does not recognize the new or updated sessionparameter from the PDSN, the PCF shall indicate this to the PDSN in theA11-Registration ack message.

If a handoff of mobile station 140 occurs, base station 130 transmits tocall controller/mobility manager 117 of MSC 115 a handoff required(HO-REQ) message 155. Referring to FIG. 4, this message flow scenario isshown. The message flow scenario of FIG. 4 is the same as FIG. 2 forsteps 150 through 154. Mobile station 140 may be in a dormant or activestate. The modified A11 registration update message 151 is transmittedfrom PDSN 106 to PCF 111. A modified A9-update-A8 message 152 is sentfrom PCF 111 to base station 130. A modified A9-update-A8 ACK message153 is transmitted from base station 130 to PCF 111. The A11registration ACK message 154 is then sent from PCF 111 to PDSN 106.

Base station 130 transmits the handoff required message to callcontroller/mobility manager 117 of MSC 115 along with a new elementincluding a packet data inactivity timer and/or other packet datasession parameters such as QoS in the handoff required message 155. Basestation 130 then becomes the source base station. The source basestation 130 passes the inactivity parameter or other packet sessionparameters such as QoS along with it to the MSC. The MSC manager 117then generates a handoff request (HO-REQUEST) message 156 which istransmitted to target base station 120. The handoff request message 156includes the inactivity timer or other system parameter such as qualityof service information.

As can be seen, with minimal modification to source base station 130 toforward the packet data inactivity timers, MSC 115 to forward thismodified handoff required message and target base station 120 to receiveand process this modified handoff request message 15. This modificationhas minimal impact on existing radio access elements and mobileswitching center elements. Further, existing handoff request messages156 are modified to include the inactivity timer and/or any updatedsession parameters, such as quality of service.

The above-mentioned modifications are easily retrofitable to theexisting RAN and mobile switch equipment to further enhance thetransmission of system parameters during a handoff. These modificationsare relatively easily implemented in the various elements mentioned.Further, the mobile communication system so modified allows the systemparameters including the inactivity timers, to be passed into the RANfrom packet data serving nodes without tearing down the connectionsthat, according to standards, would normally be torn down.

Although the preferred embodiment of the invention has been illustrated,and that form described in detail, it will be readily apparent to thoseskilled in the art that various modifications may be made thereinwithout departing from the spirit of the present invention or from thescope of the appended claims.

1-28. (canceled)
 29. In a radio access network (RAN), a method fortransmitting a packet data service inactivity timer form a packet dataserving node (PDSN) to a packet control function (PCF), the RANincluding a base station (BS), the method comprising: establishing adormant/active session from a mobile station (MS) to the PDSN throughthe RAN and the PCF; obtaining by the PDSN for the at least one packetdata service, the packet data service inactivity timer; transferring bythe PDSN a session update message including a particular sessionparameter to the PCF; determining by the BS that a handoff is required;and sending by the BS a handoff required message including sessionparameters for each packet data service supported by the MS to a mobileswitching center (MSC).
 30. The method of claim 29, wherein there isfurther included the step of sending by the MSC a handoff requestmessage including the session parameters associated with each service toa second base station.
 31. The method of claim 29, wherein there isfurther included the step of maintaining the packet data serviceinactivity timer associated with the at least one packet data servicesupported by a call.
 32. The method of claim 31, further comprising:transmitting a first update message from the packet data serving node tothe packet control function; and transmitting a second update messagefrom the packet control function to the base station.
 33. The method ofclaim 32, further comprising: responsive to the step of transmitting thesecond update message, transmitting a second update messageacknowledgment from the base station to the packet control function; andresponsive to the step of transmitting the second update message,transmitting a first update message acknowledgment from the packetcontrol function to the packet data server.